Chemical and Drilling Free, Card PCBs





Introduction: Chemical and Drilling Free, Card PCBs

About: Freelance audio designer. Into valves and hybrid gear. Dabbles in astronomy.

Most of us who are into electronics feel the need to produce a PCB for our new project. However, if like me you cant etch at home you're limited to using strip-board. The obvious alternative, getting a prototype PCB made is both expensive and fraught with difficulties. What if you pay your money but find that your layout oscillates or the component(s) you've been using go obsolete, or you've miscalculated the mechanical parts and you cant get it to fit into your case aghhhh!

These are all too common problems that I have encountered several times over the years. The only inexpensive part of the design process is the use of the computer. Recently I decided to buy some strip-board only to find it had been discontinued by my usual supplier. This set me thinking, if I can't roll my own boards or obtain strip-board then I'd have to find another hobby, or find a better way of producing boards. In a previous life I used to design electronic kits for a well known supplier. Unfortunately he didn't like spending money on PCBs . On one kit he insisted that he couldn't afford to sell it unless I did away with the PCB. So in a fit of pique I mounted the parts on a sheet of white card. I got my commission and my client was happy. Since the 1980's, computers have become widely available and PCB design programs are freely available on the net. Eagle springs to mind for example and there are some others. So the question is can you match using a nice cheap material like card and computer graphics to produce a board? The answer is yes!

Step 1: Wiring

Reverse side of early prototype showing point to point wiring. Please go to next step.

Step 2: Materials Required

Card , overlay and track prints, glue stick, scissors hammer, Paper Mache box (from 'Hobbycraft ) and or normal card, see text, push pin and large self tapping screw (not shown)

Step 3: Tools Required

Shown above the blue object is the head of a suitable push pin (rabbit headed ones should be avoided!) Also the hammer that I used. If it looks a little like overkill it is. I inherited it from my late father and I'm kind of attached to it.

Lastly but not least a piece of corrugated cardboard (not shown). It's function is to go underneath the board to allow easy hole making.

Step 4: Making a Board

Actually making a board is quite straightforward. First though a word about suitable card. Cardboard is an ubiquitous material but most of it is unsuitable for board manufacture. The thin corrugated card, used for most packing cases is definitely unsuitable. It folds easily and is incapable of standing rough handling. The best material that I have found comes from dismantling paper Mache boxes. These can be found at modeling shops for a reasonable price. This material is quite thick and is best suited to discrete devices like the transistor amp module shown. If you’re going to use IC's then normal card, as obtained in good stationers is suitable. The reason is simply that the IC pins get lost with the thicker Mache material.

Whichever material you are using the first task is to cut out your layout drawings with a pair of scissors. Glue the overlay to the card. Carefully trim the card to match the board edge. If you have printed out the trackside as a mirrored 1:1 image you can glue this to reverse side of your card. if you aligned these properly then you will have a guide to making the connections once the components have been added.

Next comes mounting the components. Put your card, overlay face up on a piece of scrap corrugated cardboard. Almost any old piece of box will fulfill this function. Take the large self tapping screw and use it like a centre punch to make an indent with the sharp end where you want your holes to be. Take care with IC pins as these are rather unforgiving of errors. Now using the push pin as a punch we can make the component mounting holes through the indents. The hammer is optional but pushing the pin through with your hand makes your thumb ache! If you've mounted the track layout correctly you should find your pinholes coincide with the component holes.

Using a pin has the extra benefit of a hole which reduces in diameter on the track side due to its point. As a result components are held firmly in place by the board when inserted. Drill a conventional hole and the parts become unsteady and easily wiggle about, even after soldering.

Insert the components one by one and solder their leads directly together to make the appropriate connections. Follow the track diagram. Connecting components together directly substantially cuts down on the number of connections required compared to a conventional PCB. Audio buffs like myself would say this is a distinct quality advantage. Its also necessary to use a little single core hookup wire to make longer connections. If you have board with a few top sided connections these can also be made with single core wire using the cable’s sleeving as insulation

What you should end up with is a functioning analog of the board that you designed. Any problems you find can be tackled at this stage before ordering a professionally made board. Of course for people like me, one design a week merchants this idea is a Godsend. Not only do I get a better functioning prototype but I also get to design a board for possible future use.



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    11 Discussions


    Your way to make pcb's is astonishing simple and straightforward. It has indeed some limitations, just as any other ways. The cardboard structure needed for this idea, has to be tried thoroughly to find the most suitable for this application.

    Honestly This is a point I haven't fully understood in your writing, anyway....

    I'm almost a "veteran" in electronics and I came to a point where I make everything I need, using standard experimental breadboards, in FR3 material. Like the one in the enclosed image. But your system has something more: the possibility to add a *very good* silkscreen, using simple instruments like a pc and a drawing program!

    The possibility to use a pin to make all the holes needed, is really a exceptionally clever point, and is always underestimated in making pcb's: the holes needed for a pot, for a cap, a power resistor, and any other strange device you can add in your pcb, are always source of under-refinement of the finished product.

    Not talking for mm spaced pins vs the mils-spaced ones!!! You simply cannot use a board like the one I use, when you face such strange pinout steps!!! :-P

    A suggestion:
    If I could "add" something to your clever system, is that you, just as you did with the components placing on top (the silkscreen) you could also glue (*) the drawing of the actual tracks you have to connect on the bottom side. This could help not to make errors when you flip upside down the board and possibly get confused by IC pin numbering. Also in both drawings you can add notes on ANYTHING you need to apply.

    So congratulations, and just as mgingerich said: "Why didn't I think of that?"



    (*) nowadays one can also use the self adhesive sheets that are widely available for any kind of printers!!!

    1 reply

    thanks for your kind comments. As for the genesis of the idea. It was simply because I had greif trying the alternative ways of producing pcbs that the creative juices flowed. This method was the result. Sometimes it pays to be frustrated by the conventional solutions!

    empty breakfast cereal boxes may be a decent compromise between the thickness of the paper mache boxes and the regular stationer's card.

    Normal card is fine for all normal designs and ideal for IC circuits. The paper mâché box is also an excellent material because it is considerably thicker it's difficult to use with ICs bot comes into its own for discrete designs.
    The only limitations with normal card i that it may be difficult to mount. I usually employ self adhesive pads. Hop this explains it better

    This is one of those cool ideas that makes people say "Why didn't I think of that?"

    I have seen a paperduino once. great idea

    I like this!!! Some early circuit boards were cloth dipped in resin or beeswax. Be interesting for you to try those. Beeswax can also act like a nontoxic and noncaustic flux as well as a protectant.

    1 reply

    What I mentioned above might have been vague: I meant dipping your board in wax(bee is yellowish/tan or canning:clear) vs the cloth.

    Fender produced an amplifier called the Tremolux, which had a leatheroid type strip with eylets punched into it, and all the components were then soldered to the eylets.

    The cardboard circuit board I used to use for prototyping, and a lot more reliable than some breadboards.

    This is a REALLY useful idea! =D I might use this... (credit will be given). More people should know about this!!

    Nice work. Thanks for sharing this handy instructable!